1. Field Of The Invention
The present invention relates to a method and apparatus providing selective dual gravel packing of a well to enable production to depletion from a lower strata and then switching to an upper strata for production to depletion.
2. The Prior Art
It is well known that a single yell bore will penetrate a plurality of vertically spaced production zones. In order to effectively and efficiently remove the hydrocarbons from the respective producing zones, it is preferable to work a single zone at a time in order to be able to ascertain the effectiveness of any secondary or enhanced oil recovery procedures being used. Heretofore this has been accomplished by using a sliding sleeve gravel pack. However such sleeves are subject to corrosion problems which can inhibit sliding thereby making the tool inoperative. Thus production from an additional zone can be prevented simply because the tool in the wellbore blocks access to that layer. It is, of course, possible to remove the sliding sleeve tool and replace it with another. However, this requires the expenditure of a substantial amount of time and expense.
The present invention has as an object to overcome the above mentioned corrosion problem by providing a dual gravel packing tool and method for using the tool to selectively produce oil from individual zones.